/**
 * @author aleeper / http://adamleeper.com/
 * @author mrdoob / http://mrdoob.com/
 * @author gero3 / https://github.com/gero3
 *
 * Description: A THREE loader for STL ASCII files, as created by Solidworks and other CAD programs.
 *
 * Supports both binary and ASCII encoded files, with automatic detection of type.
 *
 * Limitations:
 *    Binary decoding supports "Magics" color format (http://en.wikipedia.org/wiki/STL_(file_format)#Color_in_binary_STL).
 *    There is perhaps some question as to how valid it is to always assume little-endian-ness.
 *    ASCII decoding assumes file is UTF-8. Seems to work for the examples...
 *
 * Usage:
 *    var loader = new THREE.STLLoader();
 *    loader.addEventListener( 'load', function ( event ) {
 *
 * 		var geometry = event.content;
 * 		scene.add( new THREE.Mesh( geometry ) );
 *
 * 	} );
 *    loader.load( './models/stl/slotted_disk.stl' );
 *
 * For binary STLs geometry might contain colors for vertices. To use it:
 *  ... // use the same code to load STL as above
 *  var geometry = event.content;
 *  if (geometry.hasColors) {
 *    material = new THREE.MeshPhongMaterial({ opacity: geometry.alpha, vertexColors: THREE.VertexColors });
 *  } else { .... }
 * var mesh = new THREE.Mesh( geometry, material );
 */


THREE.STLLoader = function () {
};

THREE.STLLoader.prototype = {

    constructor: THREE.STLLoader

};

THREE.STLLoader.prototype.load = function (url, callback) {

    var scope = this;

    var xhr = new XMLHttpRequest();

    function onloaded(event) {

        if (event.target.status === 200 || event.target.status === 0) {

            var geometry = scope.parse(event.target.response || event.target.responseText);

            scope.dispatchEvent({ type: 'load', content: geometry });

            if (callback) callback(geometry);

        } else {

            scope.dispatchEvent({ type: 'error', message: 'Couldn\'t load URL [' + url + ']', response: event.target.statusText });

        }

    }

    xhr.addEventListener('load', onloaded, false);

    xhr.addEventListener('progress', function (event) {

        scope.dispatchEvent({ type: 'progress', loaded: event.loaded, total: event.total });

    }, false);

    xhr.addEventListener('error', function () {

        scope.dispatchEvent({ type: 'error', message: 'Couldn\'t load URL [' + url + ']' });

    }, false);

    if (xhr.overrideMimeType) xhr.overrideMimeType('text/plain; charset=x-user-defined');
    xhr.open('GET', url, true);
    xhr.responseType = 'arraybuffer';
    xhr.send(null);

};

THREE.STLLoader.prototype.parse = function (data) {


    var isBinary = function () {

        var expect, face_size, n_faces, reader;
        reader = new DataView(binData);
        face_size = (32 / 8 * 3) + ((32 / 8 * 3) * 3) + (16 / 8);
        n_faces = reader.getUint32(80, true);
        expect = 80 + (32 / 8) + (n_faces * face_size);
        return expect === reader.byteLength;

    };

    var binData = this.ensureBinary(data);
    return isBinary()
        ? this.parseBinary(binData)
        : this.parseASCII(this.ensureString(data));

};

THREE.STLLoader.prototype.parseBinary = function (data) {

    var reader = new DataView(data);
    var faces = reader.getUint32(80, true);

    var r, g, b, hasColors = false, colors;
    var defaultR, defaultG, defaultB, alpha;

    // process STL header
    // check for default color in header ("COLOR=rgba" sequence).
    for (var index = 0; index < 80 - 10; index++) {

        if ((reader.getUint32(index, false) == 0x434F4C4F /*COLO*/) &&
            (reader.getUint8(index + 4) == 0x52 /*'R'*/) &&
            (reader.getUint8(index + 5) == 0x3D /*'='*/)) {

            hasColors = true;
            colors = new Float32Array(faces * 3 * 3);

            defaultR = reader.getUint8(index + 6) / 255;
            defaultG = reader.getUint8(index + 7) / 255;
            defaultB = reader.getUint8(index + 8) / 255;
            alpha = reader.getUint8(index + 9) / 255;
        }
    }

    var dataOffset = 84;
    var faceLength = 12 * 4 + 2;

    var offset = 0;

    var geometry = new THREE.BufferGeometry();

    var vertices = new Float32Array(faces * 3 * 3);
    var normals = new Float32Array(faces * 3 * 3);

    for (var face = 0; face < faces; face++) {

        var start = dataOffset + face * faceLength;
        var normalX = reader.getFloat32(start, true);
        var normalY = reader.getFloat32(start + 4, true);
        var normalZ = reader.getFloat32(start + 8, true);

        if (hasColors) {

            var packedColor = reader.getUint16(start + 48, true);

            if ((packedColor & 0x8000) === 0) { // facet has its own unique color

                r = (packedColor & 0x1F) / 31;
                g = ((packedColor >> 5) & 0x1F) / 31;
                b = ((packedColor >> 10) & 0x1F) / 31;
            } else {

                r = defaultR;
                g = defaultG;
                b = defaultB;
            }
        }

        for (var i = 1; i <= 3; i++) {

            var vertexstart = start + i * 12;

            vertices[ offset     ] = reader.getFloat32(vertexstart, true);
            vertices[ offset + 1 ] = reader.getFloat32(vertexstart + 4, true);
            vertices[ offset + 2 ] = reader.getFloat32(vertexstart + 8, true);

            normals[ offset     ] = normalX;
            normals[ offset + 1 ] = normalY;
            normals[ offset + 2 ] = normalZ;

            if (hasColors) {
                colors[ offset     ] = r;
                colors[ offset + 1 ] = g;
                colors[ offset + 2 ] = b;
            }

            offset += 3;

        }

    }

    geometry.addAttribute('position', new THREE.BufferAttribute(vertices, 3));
    geometry.addAttribute('normal', new THREE.BufferAttribute(normals, 3));

    if (hasColors) {
        geometry.addAttribute('color', new THREE.BufferAttribute(colors, 3));
        geometry.hasColors = true;
        geometry.alpha = alpha;
    }

    return geometry;

};

THREE.STLLoader.prototype.parseASCII = function (data) {

    var geometry, length, normal, patternFace, patternNormal, patternVertex, result, text;
    geometry = new THREE.Geometry();
    patternFace = /facet([\s\S]*?)endfacet/g;

    while (( result = patternFace.exec(data) ) !== null) {

        text = result[0];
        patternNormal = /normal[\s]+([\-+]?[0-9]+\.?[0-9]*([eE][\-+]?[0-9]+)?)+[\s]+([\-+]?[0-9]*\.?[0-9]+([eE][\-+]?[0-9]+)?)+[\s]+([\-+]?[0-9]*\.?[0-9]+([eE][\-+]?[0-9]+)?)+/g;

        while (( result = patternNormal.exec(text) ) !== null) {

            normal = new THREE.Vector3(parseFloat(result[ 1 ]), parseFloat(result[ 3 ]), parseFloat(result[ 5 ]));

        }

        patternVertex = /vertex[\s]+([\-+]?[0-9]+\.?[0-9]*([eE][\-+]?[0-9]+)?)+[\s]+([\-+]?[0-9]*\.?[0-9]+([eE][\-+]?[0-9]+)?)+[\s]+([\-+]?[0-9]*\.?[0-9]+([eE][\-+]?[0-9]+)?)+/g;

        while (( result = patternVertex.exec(text) ) !== null) {

            geometry.vertices.push(new THREE.Vector3(parseFloat(result[ 1 ]), parseFloat(result[ 3 ]), parseFloat(result[ 5 ])));

        }

        length = geometry.vertices.length;

        geometry.faces.push(new THREE.Face3(length - 3, length - 2, length - 1, normal));

    }

    geometry.computeBoundingBox();
    geometry.computeBoundingSphere();

    return geometry;

};

THREE.STLLoader.prototype.ensureString = function (buf) {

    if (typeof buf !== "string") {
        var array_buffer = new Uint8Array(buf);
        var str = '';
        for (var i = 0; i < buf.byteLength; i++) {
            str += String.fromCharCode(array_buffer[i]); // implicitly assumes little-endian
        }
        return str;
    } else {
        return buf;
    }

};

THREE.STLLoader.prototype.ensureBinary = function (buf) {

    if (typeof buf === "string") {
        var array_buffer = new Uint8Array(buf.length);
        for (var i = 0; i < buf.length; i++) {
            array_buffer[i] = buf.charCodeAt(i) & 0xff; // implicitly assumes little-endian
        }
        return array_buffer.buffer || array_buffer;
    } else {
        return buf;
    }

};

THREE.EventDispatcher.prototype.apply(THREE.STLLoader.prototype);

if (typeof DataView === 'undefined') {

    DataView = function (buffer, byteOffset, byteLength) {

        this.buffer = buffer;
        this.byteOffset = byteOffset || 0;
        this.byteLength = byteLength || buffer.byteLength || buffer.length;
        this._isString = typeof buffer === "string";

    }

    DataView.prototype = {

        _getCharCodes: function (buffer, start, length) {
            start = start || 0;
            length = length || buffer.length;
            var end = start + length;
            var codes = [];
            for (var i = start; i < end; i++) {
                codes.push(buffer.charCodeAt(i) & 0xff);
            }
            return codes;
        },

        _getBytes: function (length, byteOffset, littleEndian) {

            var result;

            // Handle the lack of endianness
            if (littleEndian === undefined) {

                littleEndian = this._littleEndian;

            }

            // Handle the lack of byteOffset
            if (byteOffset === undefined) {

                byteOffset = this.byteOffset;

            } else {

                byteOffset = this.byteOffset + byteOffset;

            }

            if (length === undefined) {

                length = this.byteLength - byteOffset;

            }

            // Error Checking
            if (typeof byteOffset !== 'number') {

                throw new TypeError('DataView byteOffset is not a number');

            }

            if (length < 0 || byteOffset + length > this.byteLength) {

                throw new Error('DataView length or (byteOffset+length) value is out of bounds');

            }

            if (this.isString) {

                result = this._getCharCodes(this.buffer, byteOffset, byteOffset + length);

            } else {

                result = this.buffer.slice(byteOffset, byteOffset + length);

            }

            if (!littleEndian && length > 1) {

                if (!(result instanceof Array)) {

                    result = Array.prototype.slice.call(result);

                }

                result.reverse();
            }

            return result;

        },

        // Compatibility functions on a String Buffer

        getFloat64: function (byteOffset, littleEndian) {

            var b = this._getBytes(8, byteOffset, littleEndian),

                sign = 1 - (2 * (b[7] >> 7)),
                exponent = ((((b[7] << 1) & 0xff) << 3) | (b[6] >> 4)) - ((1 << 10) - 1),

            // Binary operators such as | and << operate on 32 bit values, using + and Math.pow(2) instead
                mantissa = ((b[6] & 0x0f) * Math.pow(2, 48)) + (b[5] * Math.pow(2, 40)) + (b[4] * Math.pow(2, 32)) +
                    (b[3] * Math.pow(2, 24)) + (b[2] * Math.pow(2, 16)) + (b[1] * Math.pow(2, 8)) + b[0];

            if (exponent === 1024) {
                if (mantissa !== 0) {
                    return NaN;
                } else {
                    return sign * Infinity;
                }
            }

            if (exponent === -1023) { // Denormalized
                return sign * mantissa * Math.pow(2, -1022 - 52);
            }

            return sign * (1 + mantissa * Math.pow(2, -52)) * Math.pow(2, exponent);

        },

        getFloat32: function (byteOffset, littleEndian) {

            var b = this._getBytes(4, byteOffset, littleEndian),

                sign = 1 - (2 * (b[3] >> 7)),
                exponent = (((b[3] << 1) & 0xff) | (b[2] >> 7)) - 127,
                mantissa = ((b[2] & 0x7f) << 16) | (b[1] << 8) | b[0];

            if (exponent === 128) {
                if (mantissa !== 0) {
                    return NaN;
                } else {
                    return sign * Infinity;
                }
            }

            if (exponent === -127) { // Denormalized
                return sign * mantissa * Math.pow(2, -126 - 23);
            }

            return sign * (1 + mantissa * Math.pow(2, -23)) * Math.pow(2, exponent);
        },

        getInt32: function (byteOffset, littleEndian) {
            var b = this._getBytes(4, byteOffset, littleEndian);
            return (b[3] << 24) | (b[2] << 16) | (b[1] << 8) | b[0];
        },

        getUint32: function (byteOffset, littleEndian) {
            return this.getInt32(byteOffset, littleEndian) >>> 0;
        },

        getInt16: function (byteOffset, littleEndian) {
            return (this.getUint16(byteOffset, littleEndian) << 16) >> 16;
        },

        getUint16: function (byteOffset, littleEndian) {
            var b = this._getBytes(2, byteOffset, littleEndian);
            return (b[1] << 8) | b[0];
        },

        getInt8: function (byteOffset) {
            return (this.getUint8(byteOffset) << 24) >> 24;
        },

        getUint8: function (byteOffset) {
            return this._getBytes(1, byteOffset)[0];
        }

    };

}